Method for uniformly coating liquid phases on glass beads and applications thereof

Abstract

A method is provided for uniformly coating a stationary liquid phase on glass beads, which are then suitable for use as chromatographic column packing, which comprises first contacting the beads with a first solution containing a suitable surfactant in an amount effective to promote the uniform deposition on the beads of the desired liquid phase, said surfactant being selected from the group consisting of (a) a nonionic surfactant, (b) an alkylaryl polyethylene ether phosphate, of the formula ##STR1## and (c) a mixture of nonionic surfactants, and then contacting the beads with a second solution containing a stationary liquid phase, the concentration of said stationary liquid phase in said second solution, the nature of the solvent in said second solution, and the conditions of said second contacting step being selected so that a coating of said statonary liquid phase of from about 0.05 to about 0.5 percent is imparted to said beads. Glass beads coated according to the above procedure represent an advance in the art of chromatography in that columns packed with these beads exhibit improved resolution and component adsorption characteristics.

What is claimed is: 
     
       1. In the method of separating a plurality of chromatographically reactive species wherein a gas containing a plurality of said species is passed through a bed comprising a solid support, said support having a liquid phase thereon, the improvement which comprises: employing as said bed, glass beads which have been treated by the method comprising the steps of contacting the beads with a first solution containing a nonionic, polymeric surfactant, or a mixture of nonionic, polymeric surfactants of alkylene oxide repeating units of 2 or 3 carbon atoms, to promote the uniform deposition on the beads of the desired liquid phase, and being characterized by resistance to bleed at a temperature of at least 200° C., then contacting the beads with a second solution containing a stationary liquid phase under conditions selected so that a coating of said stationary liquid phase of from about 0.05 to about 0.5 percent is imparted to said beads. 
     
     
       2. The method of claim 1 wherein the concentration of said surfactant in said first solution is from about 0.05 to about 1 weight percent. 
     
     
       3. The method of claim 2 wherein the concentration of said surfactant in said first solution is from about 0.25 to about 0.3 weight percent. 
     
     
       4. The method of claim 2 wherein said second solution contains from about 1 to about 10 weight percent of said stationary liquid phase. 
     
     
       5. The method of claim 4 wherein the surfactant contains a plurality of fluorine atoms. 
     
     
       6. The method of claim 5 wherein the surfactant is selected from the group consisting of (a) a fluorinated alkyl ester corresponding to the formula ##STR12## where R is a fluorinated alkyl group; R' is H, and n is an integer of at least 5;   (b) the surfactant in (a) where R' is CH 3  ; and   (c) a mixture of the surfactants of (a) and (b).   
     
     
       7. The method of claim 6 wherein said method includes the removal of excess surfactant solution between said contacting steps. 
     
     
       8. The method of claim 7 wherein said method includes the step of drying said beads to a freely flowable state following said second contacting step. 
     
     
       9. The method of claim 4 wherein the surfactant is polyoxypropylene, 40 percent ethoxylated. 
     
     
       10. In the method of measuring air-borne concentrations of chloromethylmethyl ether and bis-chloromethyl ether wherein 2,4,6-trichlorophenate derivatives of said ethers are separated and quantitatively measured by passing a fluid containing said derivatives through a bed comprising a solid support, said support having a liquid phase thereon, the improvement which comprises: employing as said bed, etched glass beads which have been treated according to the method recited in claim 1. 
     
     
       11. The method of claim 10 wherein the surfactant contains a plurality of fluorine atoms. 
     
     
       12. The method of claim 11 wherein the surfactant is selected from the group consisting of (a) a fluorinated alkyl ester corresponding to the formula ##STR13## where R is a fluorinated alkyl group; R' is H, and n is an integer of at least 5;   (b) the surfactant in (a) where R' is CH 3  ; and   (c) a mixture of the surfactants in (a) and (b).   
     
     
       13. The method of claim 10 wherein the surfactant is polyoxypropylene, 40 percent ethoxylated.